1. Field of the Invention
The present invention relates to a method of providing security of a mobile station in a wireless access system.
2. Discussion of the Related Art
Hereinafter, a paging group and an idle mode of a mobile station, which are related to the embodiments of the present invention, will be described in brief.
FIG. 1 is a diagram illustrating an example of a paging group comprised of a plurality of base stations.
As illustrated in FIG. 1, a plurality of base stations (BS) which support an idle mode belong to a paging group to constitute a paging region.
At this time, the paging group represents a logical group. The paging group is to provide a neighboring range region that can be paged to a downlink (DL) if there is any traffic targeting a mobile station (MS). Preferably, the paging group fulfils a condition that a specific mobile station should be great enough to exist for most of time within the same paging group and should be small enough to maintain a proper level of paging load.
FIG. 1 illustrates four paging groups defined in multiple base stations located in hexagonal lattices. One base station can be included in one or more paging groups. The paging group is defined by a management system. A paging group-action backbone network message can be used in the paging group. Also, a paging controller can manage a list of mobile stations which are in an idle mode, using a paging-announce message which is one of the backbone network message, and can manage initial paging of all base stations belonging to the paging group.
The idle mode means a support operation that allows a mobile station to periodically perform downlink broadcast traffic transmission even though the mobile station is not subscribed to a specific base station when moving a wireless link condition of multiple base stations.
The mobile station can be benefited by the idle mode as action requirements related to handover and general operation requirements are removed in the idle mode. The idle mode can save the power and management resources used by the mobile station by limiting action of the mobile station so as to scan radio resources during a discrete period.
Furthermore, the idle mode provides a simple and proper mode that can notify the mobile station of downlink traffic which is pending. The idle mode can provide benefit to a network and a base station by removing a wireless interface and network handover (HO) traffic from the mobile station which is not active.